HTMLMODE_FULL_ABS_POS appears to have been used for enabling accurate
margin settings for absolutely positioned graphics objects. If it was
disabled one could not set (in HTML editor mode) separate margins for
left and right (or bottom/top) sides of the image. The setting was
disabled for Netscape and enabled for other browsers.

This patch removes the setting and unconditionally enables the feature
in HTML editor mode. All modern browsers support
margin-{left,right,bottom,top} CSS properties.

For one, it leaves detached oosplash processes behind (the forked oosplash
instance waits for the soffice.bin child forked from the original oosplash
instance in vain).  For another, it makes unavailable the soffice.bin exit code.

This reverts commits aacf55db and
62ebb119.

setting and using gb_Helper_set_ld_path and gb_Executable_EXT_for_build
is enough to factorize these out of platform/*

a lot of configuration/definition is shared between platforms that build
using gcc.
This start to regroup things that are common into 2 files
com_GCC_defs.mk and com_GCC_class.mk
this can be expanded to be, more generically com_$(COM)_defs/class

The reson for 2 files is that some step need to modfify common definitions
based on the platform and some common definitions need platform defined
value.
with these 2 files we can do a
platform - compiler - platform - compiler - platfrom
sandwich that should cover every scenario.

This one is pretty bad, especially for those who like to select
ranges using keyboard.

The sd library uses SDI headers, but the corresponding targets
were not declared anywhere.

In some cases like an OLE object inside a textbox, the imported document
was empty. This was due to unremoved text context in dmapper.